1. Field of the Invention
The present invention relates to a liquid crystal display (LCD), and a driving method thereof. More particularly, the present invention relates to an LCD that can minimize a leakage current and reduce power consumption, and a driving method thereof.
2. Description of the Related Art
As a representative display device, a liquid crystal display (LCD) includes two display panels provided with pixel electrodes and a common electrode and a liquid crystal layer having dielectric anisotropy and interposed between the two panels. The pixel electrodes are arranged in a matrix format and are connected to a switch such as a thin film transistor (TFT) to sequentially receive a data voltage by row. The common electrode is formed over the entire surface of the display panel to receive a common voltage. The pixel electrodes, the common electrode, and the liquid crystal layer interposed between the pixel electrodes and the common electrode form a liquid crystal capacitor from a circuital view, and the liquid crystal capacitor and a switch connected thereto become a basic unit forming a pixel.
In the liquid crystal display (LCD), an electric field is generated in the liquid crystal layer by applying voltages to the two electrodes, and transmittance of light passing through the liquid crystal layer is controlled by controlling the electric field to thereby display a desired image. The LCD inverts the voltage polarity of a data signal for a common voltage for each frame, row, or pixel in order to prevent a degradation phenomenon that occurs when an electric field is applied in one direction to the liquid crystal layer for a long time.
For reducing power consumption of the LCD, data is written in the plurality of pixels during a short data writing period and light emission of the plurality of pixels is maintained during a long sustain period. During the sustain period, a voltage of each pixel should be maintained in a constant level. A leakage current may be generated in a pixel due to a characteristic of a TFT used in the pixel, and the voltage of each pixel may not be constantly maintained due to the leakage current. The leakage current causes image deterioration such as luminance change, line patterns, or cross-talk.
When capacitance of a capacitor that maintains the voltage of each pixel is increased, the influence of the leakage current can be decreased and the voltage of each pixel can be maintained in a constant level for a long period of time. However, when the capacitance is increased, power consumption may be increased and a circuit structure may be complicated.
Thus, a method for reducing the leakage current without increasing the capacitance of the capacitor is required.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.